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dc.contributor.author
Muench, Steffen
dc.contributor.author
Lohmann, Ulrike
dc.date.accessioned
2020-09-10T13:15:55Z
dc.date.available
2020-09-04T20:15:15Z
dc.date.available
2020-09-10T13:15:55Z
dc.date.issued
2020-08
dc.identifier.issn
1942-2466
dc.identifier.other
10.1029/2019MS001824
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/438610
dc.identifier.doi
10.3929/ethz-b-000438610
dc.description.abstract
We present a new cloud scheme for the ECHAM‐HAM global climate model (GCM) that includes prognostic cloud fraction and allows for subsaturation and supersaturation with respect to ice separately in the cloud‐free and cloudy air. Stratiform clouds form by convective detrainment, turbulent vertical diffusion, and large‐scale ascent. For each process, the corresponding cloud fraction is calculated, and the individual updraft velocities are used to determine cloud droplet/ice crystal number concentrations. Further, convective condensate is always detrained as supercooled cloud droplets at mixed‐phase temperatures (between 235 and 273 K), and convectively detrained ice crystal number concentrations are calculated based on the updraft velocity. Finally, the new scheme explicitly calculates condensation/evaporation and deposition/sublimation rates for phase‐change calculations. The new cloud scheme simulates a reasonable present‐day climate, reduces the previously overestimated cirrus cloud fraction, and in general improves the simulation of ice clouds. The model simulates the observed in‐cloud supersaturation for cirrus clouds, and it allows for a better representation of the tropical to extra‐tropical ratio of the longwave cloud radiative effect. Further, the ice water path, the ice crystal number concentrations, and the supercooled liquid fractions in mixed‐phase clouds agree better with observations in the new model than in the reference model. Ice crystal formation is dominated by the liquid‐origin processes of convective detrainment and homogeneous freezing of cloud droplets. The simulated ice clouds strongly depend on model tuning choices, in particular, the enhancement of the aggregation rate of ice crystals.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Wiley
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.subject
clouds
en_US
dc.subject
climate model
en_US
dc.subject
cloud cover
en_US
dc.subject
ice clouds
en_US
dc.subject
cloud microphysics
en_US
dc.title
Developing a Cloud Scheme With Prognostic Cloud Fraction and Two Moment Microphysics for ECHAM‐HAM
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 4.0 International
dc.date.published
2020-08-04
ethz.journal.title
Journal of Advances in Modeling Earth Systems
ethz.journal.volume
12
en_US
ethz.journal.issue
8
en_US
ethz.pages.start
e2019MS001824
en_US
ethz.size
37 p.
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.grant
Climate Engineering by Arctic Winter Cirrus Thinning: Risks and Feasibility (AWiCiT)
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Weinheim
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03690 - Lohmann, Ulrike / Lohmann, Ulrike
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03690 - Lohmann, Ulrike / Lohmann, Ulrike
ethz.grant.agreementno
166726
ethz.grant.fundername
SNF
ethz.grant.funderDoi
10.13039/501100001711
ethz.grant.program
Projekte MINT
ethz.date.deposited
2020-09-04T20:15:20Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2020-09-10T13:16:10Z
ethz.rosetta.lastUpdated
2022-03-29T03:06:20Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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